The present invention provides novel vinyl esters of epoxidized hydroxystyrylaza compounds, as well as cured compositions prepared from said vinyl esters.
Vinyl esters are the reaction product of about equivalent amounts of a monounsaturated monocarboxylic acid and a polyepoxide. One class of vinyl esters is described in U.S. Pat. No. 3,367,992 where dicarboxylic acid half esters of hydroxyalkyl acrylates or methacrylates are reacted with polyepoxide resins. Bowen in U.S. Pat. Nos. 3,066,112 and 3,179,623 describes the preparation of vinyl esters from monocarboxylic acids such as acrylic and methacrylic acid. Bowen also describes alternate methods of preparation wherein a glycidyl methacrylate or acrylate is reacted with the sodium salt of a dihydric phenol such as bisphenol A. Vinyl ester resins based on epoxy novolac resins are described in U.S. Pat. No. 3,301,743 to Fekete et al. Fekete et al in U.S. Pat. No. 3,256,226 describe vinyl esters where the molecular weight of the polyepoxide is increased by reacting a dicarboxylic acid with the polyepoxide resin as well as acrylic acid, etc. Other functional compounds containing a group which is reactive with an epoxide group, such as an amine, mercaptan and the like, may be utilized in place of the dicarboxylic acid. All of the above-described compositions, which contain the characteristic linkages ##STR1## and terminal polymerizable vinylidene groups are classified as vinyl esters.
The vinyl ester is typically combined with a reactive diluent: a copolymerizable vinyl monomer, to alter the viscosity of the mixture, to vary the properties of the cured coating, or for other known reasons. Most any vinyl monomer may be employed which is copolymerizable with the unsaturated groups of the vinyl ester. Such monomers include both monovinyl and polyvinyl monomers. Typical monomers include the alkenyl aromatic monomers such as styrene, vinyltoluene, t-butylstyrene and the like; and alkyl and hydroxyalkyl esters of acrylic and methacrylic acid such as methyl, ethyl, propyl, butyl, cyclohexyl and hydroxyethyl, hydroxypropyl and hydroxybutyl acrylates and methacrylates. In addition to the above, other monomers are especially useful for ultraviolet light curable systems such as 2-acetoxyalkyl acrylates; pentaerythritol di-, tri- or tetra- acrylate and the like may be added in any order.
The vinyl ester and copolymerizable vinyl monomer blend is a crosslinkable vinyl ester resin which is cured by mixing in a free radical forming catalyst in an amount ranging from 0.1 to about 5 percent by weight, preferably 1 to 2 percent by weight. Examples of these catalysts are benzoyl peroxide, tertiary butyl hydroperoxide, methylethylketone peroxide and the like. It is frequently of value to add an accelerator such as N,N-dimethylaniline, cobalt naphthenate and the like.
Preparation of epoxidized substituted hydroxystyrylaza compounds is taught Ser. No. 101,048 filed Sept. 14, 1988. The process of this invention uses a substituted hydroxystyrylaza compound described by U.S. Pat. No. 4,600,767 which is incorporated herein by reference. Epoxidation of the hydroxystyrylaza compound is completed in a conventional manner by reaction with an epihalohydrin with subsequent dehydrohalogenation with a basic-acting material and finally recovering the resultant styrylaza functional glycidyl ether product.
The vinyl ester compositions of the present invention contain styrylaza groups and are derived by reaction of epoxidized hydroxystyrylaza compounds with a mono-olefinically unsaturated monocarboxylic acid. The invention consists of the vinyl esters and the vinyl ester plus solvent and/or copolymerizable vinyl monomer formulations, whether or not cured.